In a brake system disclosed by German patent DE-38 31 426 A1, a brake line leads to a wheel brake of a driven wheel from a master brake cylinder through a hydraulically controlled three-way/two-position valve, which simultaneously serves as a change-over valve and as a cut-off valve, and through an electromagnetic inlet valve, open in its de-energized state. When an anti-lock control operation is performed, pressure fluid is discharged into a low-pressure accumulator through an electromagnetic outlet valve closed in its de-energized state. A return pump supplies the fluid out of this accumulator into the brake line between the hydraulic three-way/two-position directional control valve and the inlet valve again. For a traction slip control operation, the suction side of the pump is connected to the master cylinder through the third port of the three-way/two-position directional control valve so that it can take in fluid out of the pressure fluid reservoir via the master cylinder. When the brake is not applied, the connection is established from the master brake cylinder to the suction side of the pump, while the brake line is closed. As soon as pressure is built up by the master brake cylinder, the three-way/two-position directional control valve will assume its second switch position in which the connection is established from the master brake cylinder to the wheel brake.
Hydraulic change-over valves are advantageous in economizing electric lines. It is a disadvantage, however, that a certain fluid volume for switching is required on each brake application to change the valve over, which impairs the pedal feeling at the brake pedal, since the fluid volume intake takes place abruptly when the valve closes.